Children who bask in the nighttime glow of a TV or computer don't get enough rest and suffer from poor lifestyle habits, new research from the University of Alberta has shown.

A province-wide survey of Grade 5 students in Alberta showed that as little as one hour of additional sleep decreased the odds of being overweight or obese by 28 per cent and 30 per cent, respectively. Children with one or more electronic devices in the bedroom -- TVs, computers, video games and cellphones -- were also far more likely to be overweight or obese.

"If you want your kids to sleep better and live a healthier lifestyle, get the technology out of the bedroom," said co-author Paul Veugelers, a professor in the School of Public Health, Canada Research Chair in Population Health and Alberta Innovates -- Health Solutions Health Scholar.

Veugelers, director of the Population Health Intervention Research Unit that works with the Alberta Project Promoting active Living and healthy Eating (APPLE Schools), said the research is the first to connect the dots on the relationship between sleep, diet and physical activity among kids.

Nearly 3,400 Grade 5 students were asked about their nighttime sleep habits and access to electronics through the REAL Kids Alberta survey. Half of the students had a TV, DVD player or video game console in their bedroom, 21 per cent had a computer and 17 per cent had a cellphone. Five per cent of students had all three types of devices.

Some 57 per cent of students reported using electronics after they were supposed to be asleep, with watching TV and movies being the most popular activity. Twenty-seven per cent of students engaged in three or more activities after bedtime.

Researchers found that students with access to one electronic device were 1.47 times as likely to be overweight as kids with no devices in the bedroom. That increased to 2.57 times for kids with three devices, with similar results reported among obese children.

More sleep also led to significantly more physical activity and better diet choices, researchers found.

Co-author Christina Fung noted that children today are not sleeping as much as previous generations, with two-thirds not getting the recommended hours of sleep per night. In addition to healthy lifestyle habits, a good night's sleep has been linked to better academic outcomes, fewer mood disorders and other positive health outcomes, she said.

"It's important to teach these children at an earlier age and teach them healthy habits when they are younger."

The research was published in September by the journal Pediatric Obesity, in an early online release. The REAL Kids Alberta evaluation was funded through a contract with Alberta Health.